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linux-next/include/linux/tty.h
Arnd Bergmann a4184174be alpha: drop pre-EV56 support 
All EV4 machines are already gone, and the remaining EV5 based machines
all support the slightly more modern EV56 generation as well.
Debian only supports EV56 and later.

Drop both of these and build kernels optimized for EV56 and higher
when the "generic" options is selected, tuning for an out-of-order
EV6 pipeline, same as Debian userspace.

Since this was the only supported architecture without 8-bit and
16-bit stores, common kernel code no longer has to worry about
aligning struct members, and existing workarounds from the block
and tty layers can be removed.

The alpha memory management code no longer needs an abstraction
for the differences between EV4 and EV5+.

Link: https://lists.debian.org/debian-alpha/2023/05/msg00009.html
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Acked-by: Matt Turner <mattst88@gmail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2024-05-06 12:05:00 +02:00

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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_TTY_H
#define _LINUX_TTY_H
#include <linux/fs.h>
#include <linux/major.h>
#include <linux/termios.h>
#include <linux/workqueue.h>
#include <linux/tty_driver.h>
#include <linux/tty_ldisc.h>
#include <linux/tty_port.h>
#include <linux/mutex.h>
#include <linux/tty_flags.h>
#include <uapi/linux/tty.h>
#include <linux/rwsem.h>
#include <linux/llist.h>
/*
* (Note: the *_driver.minor_start values 1, 64, 128, 192 are
* hardcoded at present.)
*/
#define NR_UNIX98_PTY_DEFAULT 4096 /* Default maximum for Unix98 ptys */
#define NR_UNIX98_PTY_RESERVE 1024 /* Default reserve for main devpts */
#define NR_UNIX98_PTY_MAX (1 << MINORBITS) /* Absolute limit */
/*
* This character is the same as _POSIX_VDISABLE: it cannot be used as
* a c_cc[] character, but indicates that a particular special character
* isn't in use (eg VINTR has no character etc)
*/
#define __DISABLED_CHAR '\0'
#define INTR_CHAR(tty) ((tty)->termios.c_cc[VINTR])
#define QUIT_CHAR(tty) ((tty)->termios.c_cc[VQUIT])
#define ERASE_CHAR(tty) ((tty)->termios.c_cc[VERASE])
#define KILL_CHAR(tty) ((tty)->termios.c_cc[VKILL])
#define EOF_CHAR(tty) ((tty)->termios.c_cc[VEOF])
#define TIME_CHAR(tty) ((tty)->termios.c_cc[VTIME])
#define MIN_CHAR(tty) ((tty)->termios.c_cc[VMIN])
#define SWTC_CHAR(tty) ((tty)->termios.c_cc[VSWTC])
#define START_CHAR(tty) ((tty)->termios.c_cc[VSTART])
#define STOP_CHAR(tty) ((tty)->termios.c_cc[VSTOP])
#define SUSP_CHAR(tty) ((tty)->termios.c_cc[VSUSP])
#define EOL_CHAR(tty) ((tty)->termios.c_cc[VEOL])
#define REPRINT_CHAR(tty) ((tty)->termios.c_cc[VREPRINT])
#define DISCARD_CHAR(tty) ((tty)->termios.c_cc[VDISCARD])
#define WERASE_CHAR(tty) ((tty)->termios.c_cc[VWERASE])
#define LNEXT_CHAR(tty) ((tty)->termios.c_cc[VLNEXT])
#define EOL2_CHAR(tty) ((tty)->termios.c_cc[VEOL2])
#define _I_FLAG(tty, f) ((tty)->termios.c_iflag & (f))
#define _O_FLAG(tty, f) ((tty)->termios.c_oflag & (f))
#define _C_FLAG(tty, f) ((tty)->termios.c_cflag & (f))
#define _L_FLAG(tty, f) ((tty)->termios.c_lflag & (f))
#define I_IGNBRK(tty) _I_FLAG((tty), IGNBRK)
#define I_BRKINT(tty) _I_FLAG((tty), BRKINT)
#define I_IGNPAR(tty) _I_FLAG((tty), IGNPAR)
#define I_PARMRK(tty) _I_FLAG((tty), PARMRK)
#define I_INPCK(tty) _I_FLAG((tty), INPCK)
#define I_ISTRIP(tty) _I_FLAG((tty), ISTRIP)
#define I_INLCR(tty) _I_FLAG((tty), INLCR)
#define I_IGNCR(tty) _I_FLAG((tty), IGNCR)
#define I_ICRNL(tty) _I_FLAG((tty), ICRNL)
#define I_IUCLC(tty) _I_FLAG((tty), IUCLC)
#define I_IXON(tty) _I_FLAG((tty), IXON)
#define I_IXANY(tty) _I_FLAG((tty), IXANY)
#define I_IXOFF(tty) _I_FLAG((tty), IXOFF)
#define I_IMAXBEL(tty) _I_FLAG((tty), IMAXBEL)
#define I_IUTF8(tty) _I_FLAG((tty), IUTF8)
#define O_OPOST(tty) _O_FLAG((tty), OPOST)
#define O_OLCUC(tty) _O_FLAG((tty), OLCUC)
#define O_ONLCR(tty) _O_FLAG((tty), ONLCR)
#define O_OCRNL(tty) _O_FLAG((tty), OCRNL)
#define O_ONOCR(tty) _O_FLAG((tty), ONOCR)
#define O_ONLRET(tty) _O_FLAG((tty), ONLRET)
#define O_OFILL(tty) _O_FLAG((tty), OFILL)
#define O_OFDEL(tty) _O_FLAG((tty), OFDEL)
#define O_NLDLY(tty) _O_FLAG((tty), NLDLY)
#define O_CRDLY(tty) _O_FLAG((tty), CRDLY)
#define O_TABDLY(tty) _O_FLAG((tty), TABDLY)
#define O_BSDLY(tty) _O_FLAG((tty), BSDLY)
#define O_VTDLY(tty) _O_FLAG((tty), VTDLY)
#define O_FFDLY(tty) _O_FLAG((tty), FFDLY)
#define C_BAUD(tty) _C_FLAG((tty), CBAUD)
#define C_CSIZE(tty) _C_FLAG((tty), CSIZE)
#define C_CSTOPB(tty) _C_FLAG((tty), CSTOPB)
#define C_CREAD(tty) _C_FLAG((tty), CREAD)
#define C_PARENB(tty) _C_FLAG((tty), PARENB)
#define C_PARODD(tty) _C_FLAG((tty), PARODD)
#define C_HUPCL(tty) _C_FLAG((tty), HUPCL)
#define C_CLOCAL(tty) _C_FLAG((tty), CLOCAL)
#define C_CIBAUD(tty) _C_FLAG((tty), CIBAUD)
#define C_CRTSCTS(tty) _C_FLAG((tty), CRTSCTS)
#define C_CMSPAR(tty) _C_FLAG((tty), CMSPAR)
#define L_ISIG(tty) _L_FLAG((tty), ISIG)
#define L_ICANON(tty) _L_FLAG((tty), ICANON)
#define L_XCASE(tty) _L_FLAG((tty), XCASE)
#define L_ECHO(tty) _L_FLAG((tty), ECHO)
#define L_ECHOE(tty) _L_FLAG((tty), ECHOE)
#define L_ECHOK(tty) _L_FLAG((tty), ECHOK)
#define L_ECHONL(tty) _L_FLAG((tty), ECHONL)
#define L_NOFLSH(tty) _L_FLAG((tty), NOFLSH)
#define L_TOSTOP(tty) _L_FLAG((tty), TOSTOP)
#define L_ECHOCTL(tty) _L_FLAG((tty), ECHOCTL)
#define L_ECHOPRT(tty) _L_FLAG((tty), ECHOPRT)
#define L_ECHOKE(tty) _L_FLAG((tty), ECHOKE)
#define L_FLUSHO(tty) _L_FLAG((tty), FLUSHO)
#define L_PENDIN(tty) _L_FLAG((tty), PENDIN)
#define L_IEXTEN(tty) _L_FLAG((tty), IEXTEN)
#define L_EXTPROC(tty) _L_FLAG((tty), EXTPROC)
struct device;
struct signal_struct;
struct tty_operations;
/**
* struct tty_struct - state associated with a tty while open
*
* @kref: reference counting by tty_kref_get() and tty_kref_put(), reaching zero
* frees the structure
* @dev: class device or %NULL (e.g. ptys, serdev)
* @driver: &struct tty_driver operating this tty
* @ops: &struct tty_operations of @driver for this tty (open, close, etc.)
* @index: index of this tty (e.g. to construct @name like tty12)
* @ldisc_sem: protects line discipline changes (@ldisc) -- lock tty not pty
* @ldisc: the current line discipline for this tty (n_tty by default)
* @atomic_write_lock: protects against concurrent writers, i.e. locks
* @write_cnt, @write_buf and similar
* @legacy_mutex: leftover from history (BKL -> BTM -> @legacy_mutex),
* protecting several operations on this tty
* @throttle_mutex: protects against concurrent tty_throttle_safe() and
* tty_unthrottle_safe() (but not tty_unthrottle())
* @termios_rwsem: protects @termios and @termios_locked
* @winsize_mutex: protects @winsize
* @termios: termios for the current tty, copied from/to @driver.termios
* @termios_locked: locked termios (by %TIOCGLCKTRMIOS and %TIOCSLCKTRMIOS
* ioctls)
* @name: name of the tty constructed by tty_line_name() (e.g. ttyS3)
* @flags: bitwise OR of %TTY_THROTTLED, %TTY_IO_ERROR, ...
* @count: count of open processes, reaching zero cancels all the work for
* this tty and drops a @kref too (but does not free this tty)
* @winsize: size of the terminal "window" (cf. @winsize_mutex)
* @flow: flow settings grouped together
* @flow.lock: lock for @flow members
* @flow.stopped: tty stopped/started by stop_tty()/start_tty()
* @flow.tco_stopped: tty stopped/started by %TCOOFF/%TCOON ioctls (it has
* precedence over @flow.stopped)
* @ctrl: control settings grouped together
* @ctrl.lock: lock for @ctrl members
* @ctrl.pgrp: process group of this tty (setpgrp(2))
* @ctrl.session: session of this tty (setsid(2)). Writes are protected by both
* @ctrl.lock and @legacy_mutex, readers must use at least one of
* them.
* @ctrl.pktstatus: packet mode status (bitwise OR of %TIOCPKT_ constants)
* @ctrl.packet: packet mode enabled
* @hw_stopped: not controlled by the tty layer, under @driver's control for CTS
* handling
* @receive_room: bytes permitted to feed to @ldisc without any being lost
* @flow_change: controls behavior of throttling, see tty_throttle_safe() and
* tty_unthrottle_safe()
* @link: link to another pty (master -> slave and vice versa)
* @fasync: state for %O_ASYNC (for %SIGIO); managed by fasync_helper()
* @write_wait: concurrent writers are waiting in this queue until they are
* allowed to write
* @read_wait: readers wait for data in this queue
* @hangup_work: normally a work to perform a hangup (do_tty_hangup()); while
* freeing the tty, (re)used to release_one_tty()
* @disc_data: pointer to @ldisc's private data (e.g. to &struct n_tty_data)
* @driver_data: pointer to @driver's private data (e.g. &struct uart_state)
* @files_lock: protects @tty_files list
* @tty_files: list of (re)openers of this tty (i.e. linked &struct
* tty_file_private)
* @closing: when set during close, n_tty processes only START & STOP chars
* @write_buf: temporary buffer used during tty_write() to copy user data to
* @write_cnt: count of bytes written in tty_write() to @write_buf
* @SAK_work: if the tty has a pending do_SAK, it is queued here
* @port: persistent storage for this device (i.e. &struct tty_port)
*
* All of the state associated with a tty while the tty is open. Persistent
* storage for tty devices is referenced here as @port and is documented in
* &struct tty_port.
*/
struct tty_struct {
struct kref kref;
int index;
struct device *dev;
struct tty_driver *driver;
struct tty_port *port;
const struct tty_operations *ops;
struct tty_ldisc *ldisc;
struct ld_semaphore ldisc_sem;
struct mutex atomic_write_lock;
struct mutex legacy_mutex;
struct mutex throttle_mutex;
struct rw_semaphore termios_rwsem;
struct mutex winsize_mutex;
struct ktermios termios, termios_locked;
char name[64];
unsigned long flags;
int count;
unsigned int receive_room;
struct winsize winsize;
struct {
spinlock_t lock;
bool stopped;
bool tco_stopped;
} flow;
struct {
struct pid *pgrp;
struct pid *session;
spinlock_t lock;
unsigned char pktstatus;
bool packet;
} ctrl;
bool hw_stopped;
bool closing;
int flow_change;
struct tty_struct *link;
struct fasync_struct *fasync;
wait_queue_head_t write_wait;
wait_queue_head_t read_wait;
struct work_struct hangup_work;
void *disc_data;
void *driver_data;
spinlock_t files_lock;
int write_cnt;
u8 *write_buf;
struct list_head tty_files;
#define N_TTY_BUF_SIZE 4096
struct work_struct SAK_work;
} __randomize_layout;
/* Each of a tty's open files has private_data pointing to tty_file_private */
struct tty_file_private {
struct tty_struct *tty;
struct file *file;
struct list_head list;
};
/**
* DOC: TTY Struct Flags
*
* These bits are used in the :c:member:`tty_struct.flags` field.
*
* So that interrupts won't be able to mess up the queues,
* copy_to_cooked must be atomic with respect to itself, as must
* tty->write. Thus, you must use the inline functions set_bit() and
* clear_bit() to make things atomic.
*
* TTY_THROTTLED
* Driver input is throttled. The ldisc should call
* :c:member:`tty_driver.unthrottle()` in order to resume reception when
* it is ready to process more data (at threshold min).
*
* TTY_IO_ERROR
* If set, causes all subsequent userspace read/write calls on the tty to
* fail, returning -%EIO. (May be no ldisc too.)
*
* TTY_OTHER_CLOSED
* Device is a pty and the other side has closed.
*
* TTY_EXCLUSIVE
* Exclusive open mode (a single opener).
*
* TTY_DO_WRITE_WAKEUP
* If set, causes the driver to call the
* :c:member:`tty_ldisc_ops.write_wakeup()` method in order to resume
* transmission when it can accept more data to transmit.
*
* TTY_LDISC_OPEN
* Indicates that a line discipline is open. For debugging purposes only.
*
* TTY_PTY_LOCK
* A flag private to pty code to implement %TIOCSPTLCK/%TIOCGPTLCK logic.
*
* TTY_NO_WRITE_SPLIT
* Prevent driver from splitting up writes into smaller chunks (preserve
* write boundaries to driver).
*
* TTY_HUPPED
* The TTY was hung up. This is set post :c:member:`tty_driver.hangup()`.
*
* TTY_HUPPING
* The TTY is in the process of hanging up to abort potential readers.
*
* TTY_LDISC_CHANGING
* Line discipline for this TTY is being changed. I/O should not block
* when this is set. Use tty_io_nonblock() to check.
*
* TTY_LDISC_HALTED
* Line discipline for this TTY was stopped. No work should be queued to
* this ldisc.
*/
#define TTY_THROTTLED 0
#define TTY_IO_ERROR 1
#define TTY_OTHER_CLOSED 2
#define TTY_EXCLUSIVE 3
#define TTY_DO_WRITE_WAKEUP 5
#define TTY_LDISC_OPEN 11
#define TTY_PTY_LOCK 16
#define TTY_NO_WRITE_SPLIT 17
#define TTY_HUPPED 18
#define TTY_HUPPING 19
#define TTY_LDISC_CHANGING 20
#define TTY_LDISC_HALTED 22
static inline bool tty_io_nonblock(struct tty_struct *tty, struct file *file)
{
return file->f_flags & O_NONBLOCK ||
test_bit(TTY_LDISC_CHANGING, &tty->flags);
}
static inline bool tty_io_error(struct tty_struct *tty)
{
return test_bit(TTY_IO_ERROR, &tty->flags);
}
static inline bool tty_throttled(struct tty_struct *tty)
{
return test_bit(TTY_THROTTLED, &tty->flags);
}
#ifdef CONFIG_TTY
void tty_kref_put(struct tty_struct *tty);
struct pid *tty_get_pgrp(struct tty_struct *tty);
void tty_vhangup_self(void);
void disassociate_ctty(int priv);
dev_t tty_devnum(struct tty_struct *tty);
void proc_clear_tty(struct task_struct *p);
struct tty_struct *get_current_tty(void);
/* tty_io.c */
int __init tty_init(void);
const char *tty_name(const struct tty_struct *tty);
struct tty_struct *tty_kopen_exclusive(dev_t device);
struct tty_struct *tty_kopen_shared(dev_t device);
void tty_kclose(struct tty_struct *tty);
int tty_dev_name_to_number(const char *name, dev_t *number);
#else
static inline void tty_kref_put(struct tty_struct *tty)
{ }
static inline struct pid *tty_get_pgrp(struct tty_struct *tty)
{ return NULL; }
static inline void tty_vhangup_self(void)
{ }
static inline void disassociate_ctty(int priv)
{ }
static inline dev_t tty_devnum(struct tty_struct *tty)
{ return 0; }
static inline void proc_clear_tty(struct task_struct *p)
{ }
static inline struct tty_struct *get_current_tty(void)
{ return NULL; }
/* tty_io.c */
static inline int __init tty_init(void)
{ return 0; }
static inline const char *tty_name(const struct tty_struct *tty)
{ return "(none)"; }
static inline struct tty_struct *tty_kopen_exclusive(dev_t device)
{ return ERR_PTR(-ENODEV); }
static inline void tty_kclose(struct tty_struct *tty)
{ }
static inline int tty_dev_name_to_number(const char *name, dev_t *number)
{ return -ENOTSUPP; }
#endif
extern struct ktermios tty_std_termios;
int vcs_init(void);
extern const struct class tty_class;
/**
* tty_kref_get - get a tty reference
* @tty: tty device
*
* Returns: a new reference to a tty object
*
* Locking: The caller must hold sufficient locks/counts to ensure that their
* existing reference cannot go away.
*/
static inline struct tty_struct *tty_kref_get(struct tty_struct *tty)
{
if (tty)
kref_get(&tty->kref);
return tty;
}
const char *tty_driver_name(const struct tty_struct *tty);
void tty_wait_until_sent(struct tty_struct *tty, long timeout);
void stop_tty(struct tty_struct *tty);
void start_tty(struct tty_struct *tty);
void tty_write_message(struct tty_struct *tty, char *msg);
int tty_send_xchar(struct tty_struct *tty, u8 ch);
int tty_put_char(struct tty_struct *tty, u8 c);
unsigned int tty_chars_in_buffer(struct tty_struct *tty);
unsigned int tty_write_room(struct tty_struct *tty);
void tty_driver_flush_buffer(struct tty_struct *tty);
void tty_unthrottle(struct tty_struct *tty);
bool tty_throttle_safe(struct tty_struct *tty);
bool tty_unthrottle_safe(struct tty_struct *tty);
int tty_do_resize(struct tty_struct *tty, struct winsize *ws);
int tty_get_icount(struct tty_struct *tty,
struct serial_icounter_struct *icount);
int tty_get_tiocm(struct tty_struct *tty);
int is_current_pgrp_orphaned(void);
void tty_hangup(struct tty_struct *tty);
void tty_vhangup(struct tty_struct *tty);
int tty_hung_up_p(struct file *filp);
void do_SAK(struct tty_struct *tty);
void __do_SAK(struct tty_struct *tty);
void no_tty(void);
speed_t tty_termios_baud_rate(const struct ktermios *termios);
void tty_termios_encode_baud_rate(struct ktermios *termios, speed_t ibaud,
speed_t obaud);
void tty_encode_baud_rate(struct tty_struct *tty, speed_t ibaud,
speed_t obaud);
/**
* tty_get_baud_rate - get tty bit rates
* @tty: tty to query
*
* Returns: the baud rate as an integer for this terminal
*
* Locking: The termios lock must be held by the caller.
*/
static inline speed_t tty_get_baud_rate(const struct tty_struct *tty)
{
return tty_termios_baud_rate(&tty->termios);
}
unsigned char tty_get_char_size(unsigned int cflag);
unsigned char tty_get_frame_size(unsigned int cflag);
void tty_termios_copy_hw(struct ktermios *new, const struct ktermios *old);
bool tty_termios_hw_change(const struct ktermios *a, const struct ktermios *b);
int tty_set_termios(struct tty_struct *tty, struct ktermios *kt);
void tty_wakeup(struct tty_struct *tty);
int tty_mode_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg);
int tty_perform_flush(struct tty_struct *tty, unsigned long arg);
struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx);
void tty_release_struct(struct tty_struct *tty, int idx);
void tty_init_termios(struct tty_struct *tty);
void tty_save_termios(struct tty_struct *tty);
int tty_standard_install(struct tty_driver *driver,
struct tty_struct *tty);
extern struct mutex tty_mutex;
/* n_tty.c */
void n_tty_inherit_ops(struct tty_ldisc_ops *ops);
#ifdef CONFIG_TTY
void __init n_tty_init(void);
#else
static inline void n_tty_init(void) { }
#endif
/* tty_audit.c */
#ifdef CONFIG_AUDIT
void tty_audit_exit(void);
void tty_audit_fork(struct signal_struct *sig);
int tty_audit_push(void);
#else
static inline void tty_audit_exit(void)
{
}
static inline void tty_audit_fork(struct signal_struct *sig)
{
}
static inline int tty_audit_push(void)
{
return 0;
}
#endif
/* tty_ioctl.c */
int n_tty_ioctl_helper(struct tty_struct *tty, unsigned int cmd,
unsigned long arg);
/* vt.c */
int vt_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg);
long vt_compat_ioctl(struct tty_struct *tty, unsigned int cmd,
unsigned long arg);
/* tty_mutex.c */
/* functions for preparation of BKL removal */
void tty_lock(struct tty_struct *tty);
int tty_lock_interruptible(struct tty_struct *tty);
void tty_unlock(struct tty_struct *tty);
void tty_lock_slave(struct tty_struct *tty);
void tty_unlock_slave(struct tty_struct *tty);
void tty_set_lock_subclass(struct tty_struct *tty);
#endif
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